Disorder at the tips of a disease-relevant Aβ42 amyloid fibril: A molecular dynamics study

TitleDisorder at the tips of a disease-relevant Aβ42 amyloid fibril: A molecular dynamics study
Publication TypeJournal Article
Year of Publication2018
AuthorsIlie I.M, Caflisch A.
JournalThe Journal of Physical Chemistry B
Date Published2018 Jul 17
Type of ArticleResearch Article
ISSN1520-5207
Keywordsaggregation, Alzheimer Disease, Amyloid beta-Peptides, disorder, fibril elongation
Abstract

We present a simulation study of the early events of peptide dissociation from a fibril of the Alzheimer's Aβ42 peptide. The fibril consists of layers of two adjacent Aβ42 peptides each folded in an S-shaped structure which has been determined by solid state NMR spectroscopy of a monomorphic disease-relevant species. Multiple molecular dynamics runs (16 at 310 K and 15 at 370 K) were carried out starting from an 18-peptide protofibril for a cumulative sampling of about 15 μs. The simulations show structural stability of the fibrillar core and an overall increase in the twist to about 3 degrees. The N-terminal segment 1-14 is disordered in all peptides. At both ends of the fibril, the central segment 21-29, which includes part of the β2 strand, dissociates in some of the simulations. The β1 and β3 strands, residues 15-20 and 35-41, respectively, are structurally stable. The transient binding of the N-terminal stretch to the β3 strand of the adjacent peptide at the tip is likely to contribute to the arrest phase of the stop-and-go mechanism.

DOI10.1021/acs.jpcb.8b05236
pubindex

0237

Alternate JournalJ. Phys. Chem. B
PubMed ID29965774
Highlight Role: 
Aggregation and Assembly